JP2011162603A - Adhesive composition and adhesive sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive composition and an adhesive sheet having sufficient adhesive force between a base material and an adhesive layer and achieving high reliability of a semiconductor package. <P>SOLUTION: The adhesive composition includes an acrylic binder (A), an epoxy-based thermosetting compound (B) and an energy ray-curable compound (C), wherein the acrylic binder (A) contains an acrylic polymer (A1) having a mass-average molecular weight of 300,000 to 1,200,000 and an acrylic polymer (A2) having a mass-average molecular weight of 10,000 to 120,000. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention provides a step of die-bonding a semiconductor element (semiconductor chip) to an organic substrate, a lead frame, and other semiconductor chips, or a semiconductor wafer is diced and the semiconductor chip is converted into an organic substrate, a lead frame, and other semiconductor chips. The present invention relates to an adhesive composition particularly suitable for use in a die bonding process, and an adhesive sheet having an adhesive layer formed from the adhesive composition.

  Semiconductor wafers such as silicon and gallium arsenide are manufactured in a large diameter state. The semiconductor wafer is cut and separated (diced) into element pieces (semiconductor chips) and then transferred to the bonding process which is the next process. At this time, the semiconductor wafer is subjected to dicing, cleaning, drying, expanding, and pick-up processes in a state of being adhered to the adhesive sheet in advance, and then transferred to the next bonding process.

  Among these processes, various dicing / die bonding adhesive sheets having both a wafer fixing function and a die bonding function have been proposed in order to simplify the pickup process and the bonding process (for example, patents). Reference 1-5). The adhesive sheets disclosed in Patent Documents 1 to 5 enable so-called direct die bonding, and the application process of the adhesive agent for die bonding can be omitted. For example, by using the adhesive sheet, direct die bonding such as between an organic substrate and a chip, between a lead frame and a chip, and between a chip and a chip can be performed.

  Adhesive formed from an adhesive composition containing an acrylic binder and an epoxy thermosetting compound because it is excellent in manufacturability and process suitability (especially dicing suitability) of the adhesive sheet. An adhesive sheet having an agent layer is widely used.

Japanese Patent Laid-Open No. 02-032181 Japanese Patent Laid-Open No. 08-239636 Japanese Patent Laid-Open No. 10-008001 JP 2000-017246 A JP 2009-203332 A

  In recent years, in an adhesive sheet that has both a wafer fixing function and a die bonding function, there is a problem in dicing suitability such as chip jumping during dicing as the semiconductor wafer becomes thinner. One of the causes is considered to be insufficient adhesion between the base material / adhesive layer constituting the adhesive sheet. In addition, with recent miniaturization and high performance of mobile phone terminals and the like, required performance such as reliability for semiconductor packages is higher than before.

  However, in the prior art, there is still room for improvement in coexistence of sufficient adhesion between the base material / adhesive layer and high reliability of the semiconductor package, and it is hoped to provide an adhesive sheet that sufficiently satisfies these requirements. It is rare.

  An object of the present invention is to provide an adhesive composition that has sufficient adhesion between the base material / adhesive layers (and therefore has good process suitability such as dicing suitability) and enables high reliability of a semiconductor package. And providing an adhesive sheet.

  In the prior art, a high molecular weight acrylic polymer is used as an acrylic binder in order to impart sufficient adhesiveness and film forming property (processability to a sheet) to the adhesive composition. As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by using a low molecular weight acrylic polymer in addition to a high molecular weight acrylic polymer, thereby solving the present invention. It came to.

  That is, the present invention relates to the following [1] to [4].

  [1] An adhesive composition containing an acrylic binder (A), an epoxy thermosetting compound (B), and an energy ray curable compound (C), wherein the acrylic binder (A) has a mass average molecular weight. An adhesive composition comprising an acrylic polymer (A1) having a molecular weight of 300,000 to 1,200,000 and an acrylic polymer (A2) having a weight average molecular weight of 10,000 to 120,000.

  [2] The mass ratio α (= acrylic polymer (A2) / acrylic polymer (A1)) between the acrylic polymer (A1) and the acrylic polymer (A2) is 0.04 to 1.2. The adhesive composition as described in [1] above, wherein

  [3] In the above [1] or [2], the mass percentage β of the acrylic polymer (A2) with respect to the total mass in terms of solid content of the adhesive composition is 0.3 to 22%. The adhesive composition as described.

  It has the adhesive bond layer formed from the adhesive composition as described in any one of said [1]-[3], The adhesive sheet characterized by the above-mentioned.

  ADVANTAGE OF THE INVENTION According to this invention, the adhesive composition which has sufficient adhesive force between a base material / adhesive layer (Thus, process aptitude, such as dicing aptitude, is favorable), and high reliability of a semiconductor package is attained. And an adhesive sheet can be provided.

  Hereinafter, details of the adhesive composition and the adhesive sheet of the present invention will be described. Hereinafter, the adhesive layer formed from the adhesive composition of the present invention is also simply referred to as “adhesive layer”.

[Adhesive composition]
The adhesive composition of the present invention is an adhesive composition containing an acrylic binder (A), an epoxy thermosetting compound (B), and an energy ray curable compound (C), wherein the acrylic binder (A) As an acrylic polymer (A1) having a mass average molecular weight of 300,000 to 1,200,000 and an acrylic polymer (A2) having a mass average molecular weight of 10,000 to 120,000. Moreover, in order to improve the various physical properties of the said adhesive composition, you may mix | blend another component as needed. Hereinafter, each of these components will be described in detail.

Acrylic binder (A)
The adhesive composition of the present invention comprises, as an acrylic binder (A), an acrylic polymer (A1) having a weight average molecular weight of 300,000 to 1,200,000 and an acrylic polymer (A2) having a weight average molecular weight of 10,000 to 120,000. contains.

  The mass average molecular weight of the acrylic polymer (A1) is preferably 350,000 to 1,100,000, more preferably 400,000 to 1,000,000. The acrylic polymer (A1) is used for imparting sufficient adhesiveness and film forming property (processability to a sheet) to the adhesive composition. If the mass average molecular weight of the acrylic polymer (A1) is too low, the peeling force between the adhesive layer and the substrate may be increased, resulting in chip pickup failure. Moreover, when the mass average molecular weight of the acrylic polymer (A1) is too high, the adhesive layer may not follow the unevenness of the adherend, which may cause generation of voids.

  The mass average molecular weight of the acrylic polymer (A2) is preferably 11,000 to 115,000, more preferably 12,000 to 113,000. By using the acrylic polymer (A2) having a mass average molecular weight within the above range together with the acrylic polymer (A1), the adhesion between the substrate and the adhesive layer can be improved. If the weight average molecular weight of the acrylic polymer (A2) is too low, bleeding out from the adhesive layer may occur.

  The mass average molecular weights of the acrylic polymer (A1) and the acrylic polymer (A2) are polystyrene conversion values measured by a gel permeation chromatography (GPC) method, and the measurement conditions are as described in the examples. It is.

  In the adhesive composition of the present invention, the mass ratio α (= acrylic polymer (A2) / acrylic polymer (A1)) between the acrylic polymer (A1) and the acrylic polymer (A2) is 0.04 to 1. .2 is preferable, and 0.05 to 1.0 is more preferable.

  In the adhesive composition of the present invention, the mass percentage β of the acrylic polymer (A2) with respect to the total mass in terms of solid content of the composition is preferably 0.3 to 22%, and 0.4 to 20%. It is more preferable that In addition, in this invention, solid content means all components other than a solvent.

  In the present invention, the mass ratio and mass percentage of the acrylic polymer (A1) and the acrylic polymer (A2) can be calculated from the blending ratio of these components when preparing the adhesive composition. For example, the adhesive composition may be prepared by blending (mixing) the acrylic polymer (A1) and the acrylic polymer (A2) such that the mass ratio is in the above range.

  When the mass ratio α and / or the mass percentage β is in the above range, process suitability such as dicing suitability and semiconductor package reliability are further improved. If the mass ratio α and the mass percentage β are both below the above range, process suitability such as dicing suitability may not be sufficiently improved. If the mass ratio α and the mass percentage β are both above the above ranges, there is a concern that the low molecular weight acrylic polymer may bleed out from the adhesive layer, which may deteriorate the reliability of the semiconductor package, and is suitable for dicing. The process suitability such as may not be sufficiently improved.

  In addition, the glass transition temperature (Tg) of an acrylic polymer (A1) and an acrylic polymer (A2) is not specifically limited.

  As a monomer (raw material monomer) which comprises an acrylic polymer (A1) and an acrylic polymer (A2), (meth) acrylic acid ester and its derivative (s) are mentioned, for example. Specific examples include (meth) acrylic acid having 1 to 18 carbon atoms in an alkyl group such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and butyl (meth) acrylate. Alkyl ester; cyclic skeletons such as (meth) acrylic acid cycloalkyl ester, (meth) acrylic acid benzyl ester, isobornyl acrylate, dicyclopentanyl acrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate, imide acrylate, etc. (Meth) acrylic acid ester having; hydroxyl-containing (meth) acrylic acid ester such as hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate; glycidyl acrylate, Such as glycidyl methacrylate, and the like. Acrylic acid, methacrylic acid, itaconic acid and the like may also be used. These may be used alone or in combination of two or more.

  Among these, as a monomer constituting the acrylic polymer (A1), an acrylic polymer having good compatibility with the epoxy thermosetting compound (B) can be obtained, so that at least a hydroxyl group-containing (meth) acrylic acid is obtained. It is preferable to use an ester. In this case, in the acrylic polymer (A1), the structural unit derived from the hydroxyl group-containing (meth) acrylic acid ester is preferably included in the range of 1 to 30% by mass, and included in the range of 3 to 20% by mass. It is more preferable.

  In addition to the above (meth) acrylic acid ester and derivatives thereof, vinyl acetate, acrylonitrile, styrene, or the like may be used as a raw material monomer as long as the object of the present invention is not impaired.

  If the acrylic binder (A), specifically, the acrylic polymer (A1) and the acrylic polymer (A2) are set so that the mass average molecular weight of the resulting polymer is within the above range, using the above raw material monomers. It can be produced according to a conventionally known method.

Epoxy thermosetting compound (B)
Various conventionally known epoxy resins can be used as the epoxy thermosetting compound (B). Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenylene skeleton type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, dicyclopentadiene type epoxy resin, biphenyl type epoxy resin, and triphenol. Examples include methane type epoxy resins, heterocyclic type epoxy resins, stilbene type epoxy resins, condensed ring aromatic hydrocarbon-modified epoxy resins, and epoxy resins containing two or more functional groups in structural units such as halides thereof. It is done. Although the epoxy equivalent of an epoxy resin is not specifically limited, It is preferable that it is 150-250 (g / eq). The epoxy equivalent is a value measured according to JIS K7236.
These epoxy resins may be used alone or in combination of two or more.

  In the adhesive composition of the present invention, the content of the epoxy thermosetting compound (B) is usually 1 to 1500 parts by mass, preferably 3 to 1000 parts by mass, with respect to 100 parts by mass of the acrylic polymer (A1). Part. If the content of the epoxy thermosetting compound (B) is less than the above range, an adhesive layer having sufficient adhesive strength may not be obtained. On the other hand, if the content of the epoxy thermosetting compound (B) exceeds the above range, the adhesive force between the adhesive layer and the substrate becomes too high, and chip pick-up failure may occur.

Energy ray curable compound (C)
Before dicing semiconductor wafers and the like, the energy ray curable compound (C) is polymerized by energy ray irradiation to adjust the elastic modulus of the adhesive layer during dicing to an appropriate range, and the adhesive after dicing Re-adhesion of layers can be prevented.

  Moreover, the adhesive force of an adhesive bond layer can be reduced in the range which does not impair process aptitude, such as dicing aptitude, by polymerizing energy-beam curable compound (C) by energy ray irradiation. For this reason, delamination between the base material and the adhesive layer can be easily performed in the semiconductor chip pick-up process.

  The energy ray curable compound (C) is a compound that polymerizes and cures when irradiated with energy rays such as ultraviolet rays and electron beams. Examples of the energy ray curable compound (C) include compounds having one or more energy ray polymerizable double bonds in the molecule, for example, acrylate compounds.

  Examples of the acrylate compounds include trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate, 1,4-butylene glycol diacrylate, 1,6- Examples include hexanediol diacrylate, polyethylene glycol diacrylate, oligoester acrylate, urethane acrylate oligomer, epoxy-modified acrylate, polyether acrylate, itaconic acid oligomer, and dicyclopentadiene skeleton-containing polyfunctional acrylate.

  The molecular weight (mass average molecular weight in the case of an oligomer or polymer) of the energy beam curable compound (C) is usually about 100 to 30,000, preferably about 200 to 9000.

  In the adhesive composition of the present invention, the content of the energy ray curable compound (C) is usually 1 to 400 parts by mass, preferably 3 to 300 parts by mass with respect to 100 parts by mass of the acrylic polymer (A1). More preferably, it is 10-200 mass parts. If the content of the energy ray curable compound (C) exceeds the above range, the adhesive strength of the adhesive layer to the organic substrate or the lead frame may be reduced.

Thermosetting agent (D)
The adhesive composition of the present invention preferably contains a thermosetting agent (D). The thermosetting agent (D) functions as a thermosetting agent for the epoxy thermosetting compound (B).

  Examples of the thermosetting agent (D) include compounds having two or more functional groups capable of reacting with an epoxy group in the molecule, such as phenolic hydroxyl groups, alcoholic hydroxyl groups, amino groups, carboxyl groups, acids. An anhydride group etc. are mentioned. In these, a phenolic hydroxyl group, an amino group, and an acid anhydride group are preferable, and a phenolic hydroxyl group and an amino group are more preferable.

  Specific examples of the thermosetting agent (D) include phenolic thermosetting agents such as novolac-type phenolic resin, dicyclopentadiene-based phenolic resin, polyfunctional phenolic resin and aralkylphenolic resin; amine-based heat such as DICY (dicyandiamide) A curing agent is mentioned. A thermosetting agent (D) may be used individually by 1 type, and may use 2 or more types together.

  In the adhesive composition of the present invention, the content of the thermosetting agent (D) is usually 0.1 to 500 parts by mass, preferably 1 to 100 parts by mass with respect to 100 parts by mass of the epoxy thermosetting compound (B). 200 parts by mass. When content of a thermosetting agent (D) is less than the said range, the sclerosis | hardenability of adhesive composition may be insufficient and the adhesive bond layer which has sufficient adhesive force may not be obtained. When the content of the thermosetting agent (D) is higher than the above range, the moisture absorption rate of the adhesive composition is increased, and the reliability of the semiconductor package may be lowered.

Curing accelerator (E)
In the present invention, a curing accelerator (E) may be used to adjust the curing rate of the adhesive composition. Examples of the curing accelerator (E) include compounds capable of accelerating the reaction between an epoxy group and a phenolic hydroxyl group. Specifically, triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, tris ( Tertiary amines such as dimethylaminomethyl) phenol; imidazoles such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole; tributylphosphine, And organic phosphines such as diphenylphosphine and triphenylphosphine; and tetraphenylboron salts such as tetraphenylphosphonium tetraphenylborate and triphenylphosphinetetraphenylborate. A hardening accelerator (E) may be used individually by 1 type, and may use 2 or more types together.

  In the adhesive composition of the present invention, the content of the curing accelerator (E) is preferably 0.001 with respect to a total of 100 parts by mass of the epoxy thermosetting compound (B) and the thermosetting agent (D). -100 mass parts, More preferably, it is 0.01-50 mass parts, More preferably, it is 0.1-10 mass parts.

Photopolymerization initiator (F)
When using the adhesive composition of the present invention, it is preferable to irradiate energy rays such as ultraviolet rays to prevent re-adhesion of the adhesive layer or to reduce the adhesive force. By including the photopolymerization initiator (F) in the adhesive composition, the polymerization / curing time and the amount of light irradiation can be reduced.

  As the photopolymerization initiator (F), benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, benzoin methyl benzoate, benzoin dimethyl ketal, 2,4-diethyl Thioxanthone, 1-hydroxy-cyclohexyl-phenyl ketone, benzyldiphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzyl, dibenzyl, diacetyl, 1,2-diphenylmethane, 2,4,6-trimethylbenzoyl Examples thereof include diphenylphosphine oxide and β-chloranthraquinone. A photoinitiator (F) may be used individually by 1 type, and may use 2 or more types together.

  In the adhesive composition of the present invention, the content of the photopolymerization initiator (F) is usually 0.1 to 10 parts by mass, preferably 1 to 100 parts by mass with respect to 100 parts by mass of the energy ray curable compound (C). 5 parts by mass. When the content of the photopolymerization initiator (F) is lower than the above range, satisfactory pick-up property may not be obtained due to insufficient photopolymerization, and when it exceeds the above range, a residue that does not contribute to the photopolymerization is generated and adhered. The curability of the agent composition may be insufficient.

Coupling agent (G)
In the present invention, a coupling agent (G) may be used in order to improve the adhesion and adhesion of the adhesive composition to the adherend. Moreover, the water resistance can be improved by using a coupling agent (G), without impairing the heat resistance of the hardened | cured material obtained by hardening | curing adhesive composition.

  As the coupling agent (G), a compound having a group that reacts with a functional group of the acrylic binder (A), the epoxy thermosetting compound (B), or the like is preferably used. As the coupling agent (G), a silane coupling agent is preferable.

  As silane coupling agents, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ- (methacrylopropyl) Trimethoxysilane, γ-aminopropyltrimethoxysilane, N-6- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-6- (aminoethyl) -γ-aminopropylmethyldiethoxysilane, N-phenyl -Γ-aminopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, bis (3-triethoxysilylpropyl) tetrasulfane, methyltrimethoxysilane , Methyltri Examples include ethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, and imidazolesilane. A silane coupling agent may be used individually by 1 type, and may use 2 or more types together.

  In the adhesive composition of the present invention, the content of the coupling agent (G) is usually 0.1 to 100 parts by mass in total of the acrylic binder (A) and the epoxy thermosetting compound (B). 20 parts by mass. If the content of the coupling agent (G) is lower than the above range, the above effect may not be obtained, and if it exceeds the above range, it may cause outgassing.

Inorganic filler (H)
In the present invention, an inorganic filler (H) may be used. By blending the inorganic filler (H) into the adhesive composition, the thermal expansion coefficient of the composition can be adjusted. By optimizing the thermal expansion coefficient of the adhesive layer after curing with respect to the semiconductor chip, the lead frame, and the organic substrate, the package reliability can be further improved. In addition, it is possible to further reduce the moisture absorption rate after curing of the adhesive layer.

  Examples of the inorganic filler (H) include powders such as silica, alumina, talc, calcium carbonate, titanium white, bengara, silicon carbide, boron nitride, beads formed by spheroidizing these, single crystal fibers, glass fibers, and the like. Among these, silica filler and alumina filler are preferable. An inorganic filler (H) may be used individually by 1 type, and may use 2 or more types together.

  In the adhesive composition of the present invention, the content of the inorganic filler (H) is usually 0 to 80% by mass with respect to the total mass in terms of solid content of the adhesive composition.

Other Components The adhesive composition of the present invention may contain various additives as necessary in addition to the above-described components. Examples of various additives include flexible components, plasticizers, antistatic agents, antioxidants, pigments, and dyes.

  The adhesive composition of the present invention has adhesiveness (for example, pressure-sensitive adhesiveness) and heat curable properties, and has a function of temporarily holding various adherends in an uncured state. In particular, since the adhesive layer formed from the adhesive composition is excellent in adhesiveness with a substrate, process suitability such as dicing suitability is good. In addition, it is possible to give a cured product with high impact resistance through heat curing, and it has an excellent balance between shear strength and peel strength, and maintains sufficient adhesion even under severe heat and humidity conditions. obtain.

  The adhesive composition of the present invention is obtained by mixing each of the above components at an appropriate ratio. In mixing, each component may be diluted with a solvent in advance, or a solvent may be added during mixing.

  The adhesive composition of the present invention can be suitably used as a material for forming an adhesive layer constituting a so-called dicing sheet, die bonding sheet, dicing die bonding sheet, particularly a dicing die bonding sheet.

[Adhesive sheet]
The adhesive sheet of this invention has the adhesive bond layer formed from the said adhesive composition, Usually, this adhesive bond layer is formed on a base material. The shape of the adhesive sheet of the present invention can be any shape such as a tape shape or a label shape.

  As the base material of the adhesive sheet, polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polyethylene naphthalate film, polybutylene terephthalate film , Polyurethane film, ethylene vinyl acetate copolymer film, ionomer resin film, ethylene / (meth) acrylic acid copolymer film, ethylene / (meth) acrylic acid ester copolymer film, polystyrene film, polycarbonate film, polyimide film, Transparent films such as fluororesin films; colored transparent films or colored opaque films obtained by coloring the transparent films; Such as bridge film or a laminated film, and the like.

  The adhesive sheet of the present invention is preferably irradiated with energy rays such as ultraviolet rays from the substrate side when used, and therefore the substrate is preferably transparent to the energy rays.

  Also, usually, the adhesive sheet of the present invention is affixed to an adherend such as a semiconductor wafer, and after subjecting the adherend to the required processing, the adhesive layer remains adhered to the adherend and peels off from the substrate. To do. That is, it is suitably used for a process including a step of transferring the adhesive layer from the base material to the adherend. For this reason, the surface tension of the surface in contact with the adhesive layer of the substrate is preferably 40 mN / m or less, more preferably 37 mN / m or less, and particularly preferably 35 mN / m or less. The lower limit is usually about 25 mN / m. Such a substrate having a low surface tension can be obtained by appropriately selecting the material, and can also be obtained by applying a release agent to the surface of the substrate and performing a release treatment.

  As the release agent used for the substrate release treatment, release agents such as alkyd, silicone, fluorine, unsaturated polyester, polyolefin, and wax are used. In particular, alkyd, silicone, and fluorine are used. The release agent is preferable because it has heat resistance.

  In order to release the surface of the substrate using the above release agent, the release agent is used without a solvent, or diluted or emulsified with a solvent, and (1) a gravure coater, a Mayer bar coater, an air knife coater, a roll coater, etc. The release agent is applied to the surface of the substrate and cured at room temperature, heat, or electron beam, or (2) wet lamination, dry lamination, hot melt lamination, melt extrusion lamination, coextrusion processing, etc. Thus, a laminate of the base material and the layer made of the release agent may be formed.

  The thickness of a base material is 10-500 micrometers normally, Preferably it is 15-300 micrometers, Most preferably, it is about 20-250 micrometers. The thickness of the adhesive layer is usually 1 to 500 μm, preferably 5 to 300 μm, particularly preferably about 10 to 150 μm.

  The production method of the adhesive sheet is not particularly limited, and may be produced by applying and drying an adhesive composition constituting the adhesive layer on the substrate, and the adhesive layer is provided on the release film, You may manufacture by transferring this to the said base material. In addition, in order to protect an adhesive bond layer before using an adhesive sheet, you may laminate | stack a peeling film on the upper surface of an adhesive bond layer. In addition, a (viscous) adhesive layer or (viscous) adhesive tape may be separately provided on the outer peripheral portion of the surface of the adhesive layer in order to fix another jig such as a ring frame.

[Method of Manufacturing Semiconductor Device]
The method of using the adhesive sheet of the present invention will be described taking as an example the case where the adhesive sheet is applied to the manufacture of a semiconductor device (for example, a semiconductor package). A method for manufacturing a semiconductor device includes attaching a semiconductor wafer to the adhesive layer of the adhesive sheet, dicing the semiconductor wafer into a semiconductor chip, and fixing the adhesive layer to the back surface of the semiconductor chip and peeling it from the substrate. And placing the semiconductor chip on the die pad portion or another semiconductor chip via the adhesive layer.
Details of the method for manufacturing the semiconductor device will be described below.

  In the semiconductor device manufacturing method, first, one surface of the semiconductor wafer and the ring frame are placed on the adhesive layer of the adhesive sheet of the present invention, and lightly pressed to fix the semiconductor wafer. Next, the semiconductor wafer is cut using a cutting means such as a dicing saw to obtain a semiconductor chip. The cutting depth at this time is a depth that takes into account the sum of the thickness of the semiconductor wafer and the adhesive layer and the wear of the dicing saw.

  Since the adhesive layer contains the energy ray curable compound (C), the adhesive layer is irradiated with energy rays from the substrate side to increase the cohesive force of the adhesive layer, and adhesion between the adhesive layer and the substrate. Keep power down. Examples of the energy rays to be irradiated include ultraviolet rays (UV) and electron beams (EB), and preferably ultraviolet rays are used. The energy beam irradiation may be performed at any stage after the semiconductor wafer is pasted to before the semiconductor chip is peeled off (pickup), but the elastic modulus of the adhesive layer during dicing is adjusted to an appropriate range, and From the viewpoint of preventing re-adhesion of the adhesive layer after dicing, it is preferably performed before dicing. Further, the energy beam irradiation may be performed in a plurality of times.

  Then, if necessary, when the adhesive sheet is expanded, the interval between the semiconductor chips is expanded, and the semiconductor chips can be picked up more easily. At this time, a deviation occurs between the adhesive layer and the base material, the adhesive force between the adhesive layer and the base material is reduced, and the pick-up property of the semiconductor chip is improved.

  When the semiconductor chip is picked up in this manner, the cut adhesive layer can be fixedly left on the back surface of the semiconductor chip and peeled off from the substrate.

  Next, the semiconductor chip is mounted on the organic substrate or the die pad portion of the lead frame or another semiconductor chip (lower chip) on the lower stage through the adhesive layer. The die pad part or the lower chip is heated before mounting the semiconductor chip or immediately after mounting. The heating temperature is usually 80 to 200 ° C., preferably 100 to 180 ° C., the heating time is usually 0.1 seconds to 5 minutes, preferably 0.5 seconds to 3 minutes, and the pressure during mounting is usually 1 kPa to 200 MPa.

  After the semiconductor chip is placed on the die pad portion or the lower chip, heating may be further performed as necessary. The heating conditions at this time are in the above heating temperature range, and the heating time is usually 1 to 180 minutes, preferably 10 to 120 minutes.

  Alternatively, the adhesive layer may be cured by using heat in resin sealing that is normally performed in package manufacturing, without temporarily performing the heat treatment after placement. In that case, in order to harden sealing resin, the heating for about 2 to 8 hours is normally performed at 150-180 degreeC. Instead of the above heat treatment, a heat treatment in the sealing step may be used.

  Through such a process, the adhesive layer is cured, and the semiconductor chip and the die pad portion or the lower chip can be firmly bonded. Since the adhesive layer is fluidized under die bonding conditions, the adhesive layer is sufficiently embedded in the unevenness of the die pad portion or the lower chip, and generation of voids can be prevented.

  That is, in the obtained mounting product, the adhesive which is a fixing means of the semiconductor chip is cured and is sufficiently embedded in the unevenness of the die pad portion or the lower chip, so even under severe conditions Sufficient package reliability is achieved.

  In addition, in the manufacturing method of the semiconductor chip device including the step of placing the semiconductor chip on the other semiconductor chip via the adhesive layer, the other semiconductor chip placed on the die pad portion of the organic substrate or the lead frame A step of placing the semiconductor chip on the adhesive layer on the top, or placing the semiconductor chip on the organic substrate or another semiconductor chip not placed on the die pad portion of the lead frame via the adhesive layer It includes a process.

  The adhesive composition and adhesive sheet of the present invention can be used for bonding semiconductor compounds, glass, ceramics, metals, etc., in addition to the above-described methods of use.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples. In the following examples and comparative examples, each evaluation was performed as follows.

[Manufacture of semiconductor chips]
The adhesive sheet obtained in the example or comparative example is attached to the polished surface of a dry-polished silicon wafer (200 mm diameter, 40 μm thickness) with a tape mounter (Adwill RAD2500, manufactured by Lintec) and fixed to the ring frame for wafer dicing. did. Thereafter, ultraviolet rays were irradiated from the substrate side of the adhesive sheet to cure the adhesive layer with energy rays. Next, the wafer was diced into a chip size of 8 mm × 8 mm using a dicing apparatus (DIFD, DFD651). The amount of cut during dicing was such that the substrate was cut by 20 μm.

[Manufacture of semiconductor packages]
As a substrate, a circuit pattern is formed on a core material (100 μm thick 2-layer product) having a copper foil of 18 μm thickness (Mitsubishi Gas Chemical Co., Ltd., trade name: BT resin CCL-HL832HS), and a solder resist ( A BT substrate (manufactured by Hitachi Ultra LSI Co., Ltd.) coated with Taiyo Ink Co., Ltd. (trade name: PSR4000AUS303) was used.

  An 8mm x 8mm semiconductor chip is picked up from the base material (Canon Machinery: BESTEM DO2), and the semiconductor chip is pressure-bonded onto the substrate under the conditions of 120 ° C, 250gf, 0.5 seconds through the adhesive layer of the adhesive sheet. , 120 ° C./30 minutes, followed by heat curing under conditions of 140 ° C./30 minutes.

  Next, the semiconductor chip was sealed with a molding resin (KE-G1250 manufactured by Kyocera Chemical Co., Ltd.) so as to have a sealing thickness of 400 μm (sealing device: MPC-06M Trial Press manufactured by Apic Yamada Co., Ltd.). Thereafter, the mold resin was cured at 175 ° C. for 5 hours.

  Next, the sealed BT substrate is affixed to a dicing tape (Adwill D-510T manufactured by Lintec Co., Ltd.), and dicing into a 12 mm x 12 mm size using a dicing machine (DISCO, DFD651). A semiconductor package for property evaluation was obtained.

[Dicing suitability evaluation]
In the above item [Manufacturing of semiconductor chip], 200 silicon wafers with a diameter of 200 mm and a thickness of 40 μm were diced in a chip size of 8 mm × 8 mm, and chip skipping was visually confirmed (number of silicon wafers in which chip skipping was not observed). / Number of tests).

[Pickup evaluation]
In the above item [Manufacturing of semiconductor chips], a silicon wafer having a diameter of 200 mm and a thickness of 40 μm was diced to a chip size of 8 mm × 8 mm, and the number of chips that could be picked up out of 50 chips was counted. The apparatus used was Canon Machinery: BESTEM D02.

[Reliability evaluation]
The obtained semiconductor package was allowed to stand for 168 hours at 85 ° C. and 85% RH to absorb moisture, and then IR reflow with a maximum temperature of 260 ° C. and a heating time of 1 minute (reflow oven: WL-15-20DNX manufactured by Sagami Riko) Mold) was performed three times. The presence or absence of floating / peeling of the joints and the occurrence of package cracks were evaluated by a scanning ultrasonic flaw detector (Hye-Focus manufactured by Hitachi Construction Machinery Finetech) and cross-sectional observation. A case where peeling of an area of 0.5 mm ² or more was observed at the joint between the substrate and the semiconductor chip was judged as peeling, and 25 semiconductor packages were put into the test, and the number of peeling did not occur (OK number) ).

[Measurement method of mass average molecular weight]
The mass average molecular weights of the acrylic polymer (A1) and the acrylic polymer (A2) were measured by the following method.
・ Measurement method: Gel permeation chromatography (GPC) method ・ Standard material: polystyrene standard ・ Device: GELPERMATION CHROMATOGRAPH manufactured by Tosoh Corporation
-Column: TSK-GEL GMHXL 7.8 x 300 mm manufactured by Tosoh Corporation
・ Solvent: Tetrahydrofuran ・ Concentration: 1%
・ Injection amount: 80 μm
・ Flow rate: 1.0 ml / min

[Examples and Comparative Examples]
An adhesive composition having the composition described in Table 1 was used. In Table 1, the numerical value of each component indicates a mass part in terms of solid content. The adhesive composition having the composition shown in Table 1 was applied to a silicone-treated release film (manufactured by Lintec: PET381031) so as to have a thickness of 30 μm after drying, and dried (drying conditions: 100 ° C. in an oven for 1 minute) ), And then bonded to a polyolefin substrate (thickness: 100 μm, surface tension: 35 mN / m), and the adhesive layer was transferred onto the substrate to obtain a desired adhesive sheet.

Each material of Table 1 is as shown below.
(A-1a) Acrylic polymer A1; mass average molecular weight obtained by copolymerizing 55 parts by mass of n-butyl acrylate, 10 parts by mass of methyl acrylate, 20 parts by mass of glycidyl methacrylate, and 15 parts by mass of 2-hydroxyethyl acrylate 900,000 copolymer (A-1b) acrylic polymer A1; copolymer having a weight average molecular weight of 400,000 (A-2a) obtained by copolymerizing 85 parts by mass of methyl acrylate and 15 parts by mass of 2-hydroxyethyl acrylate ) Acrylic polymer A2; acrylic polymer mainly composed of n-butyl acrylate
(Bic Chemie: Byk-350, polymer with a mass average molecular weight of 12,000)
(A-2b) Acrylic polymer A2; acrylic polymer mainly composed of n-butyl acrylate
(Bic Chemie: Byk-352, polymer with a weight average molecular weight of 36,000)
(A-2c) Acrylic polymer A2; acrylic polymer mainly composed of n-butyl acrylate
(Bic Chemie: Byk-354, polymer with a mass average molecular weight of 113,000)
(B-1) Epoxy resin; bisphenol A type epoxy resin
(Japan Epoxy Resin: jER828, epoxy equivalent 235g / eq)
(B-2) Epoxy resin; phenylene skeleton type epoxy resin
(Nippon Kayaku Co., Ltd .: EPPN-502H, epoxy equivalent 167 g / eq)
(C) Energy ray curable compound; polyfunctional acrylate containing dicyclopentadiene skeleton (Nippon Kayaku: KAYARAD R-684, molecular weight 336)
(D) Thermosetting agent: Novolac type phenolic resin (Showa Polymer: BRG-556, phenolic hydroxyl group equivalent 103 g / eq)
(E) Curing accelerator; 2-phenyl-4,5-dihydroxymethylimidazole (Curesol 2PHZ-PW manufactured by Shikoku Kasei Kogyo Co., Ltd.)
(F) Photopolymerization initiator; 1-hydroxy-cyclohexyl-phenyl ketone (Ciba Specialty Chemicals: Irgacure 184)
(G) Silane coupling agent (Shin-Etsu Chemical Co., Ltd .: KBE-403)
(H) Inorganic filler (manufactured by Admatechs: Admafine SC2050)

  From the above results, by using the adhesive sheet of the present invention, it is possible to improve the dicing suitability without deteriorating the pick-up property, and furthermore, it is possible to obtain a semiconductor package with good reliability evaluation.

Claims (4)

  An adhesive composition containing an acrylic binder (A), an epoxy thermosetting compound (B) and an energy ray curable compound (C), wherein the acrylic binder (A) has a mass average molecular weight of 300,000 to 1,200,000. And an acrylic polymer (A2) having a weight average molecular weight of 10,000 to 120,000.   The mass ratio α (= acrylic polymer (A2) / acrylic polymer (A1)) between the acrylic polymer (A1) and the acrylic polymer (A2) is 0.04 to 1.2. The adhesive composition according to claim 1.   The adhesive composition according to claim 1 or 2, wherein a mass percentage β of the acrylic polymer (A2) with respect to a total mass in terms of solid content of the adhesive composition is 0.3 to 22%. .   It has the adhesive bond layer formed from the adhesive composition as described in any one of Claims 1-3, The adhesive sheet characterized by the above-mentioned.